The Iraqi regime could employ a "human tide" to fight US-led forces at Baghdad's airport, the leader of British forces in the Gulf has warned.
Iraq has promised a counter-attack on US troops at the Baghdad airport
Air Marshal Brian Burridge said civilians may be forced to march on the airport, to be used as human shields as Iraqi fighters try to re-take it.
The US military said its forces secured Saddam International Airport - renamed Baghdad International Airport - after fighting their way in on Thursday night.
But Iraq has warned of a "non-conventional", "non-military" act against US forces.
In an interview with BBC 2's Newsnight programme, Air Marshal Burridge said the Iraqi forces had been taken by surprise by the speed of the US-led advance on the airport - which he called an "extraordinary feat of arms".
The US forces acted so quickly the Iraqi regime had no time to decide how to respond, he said.
There were loudspeakers in south-west Baghdad signalling people should rise up and
march on the airport
Air Marshall Brain Burridge
"They weren't able to cope and comprehend what was going on.
"There have been pockets of resistance and there continue to be at the airport, but nothing like what we expected.
"The Republican Guard just didn't show."
Air Marshal Burridge also warned that any chemical or biological attack would be met with a "proportionate" response.
He told Newsnight it was "difficult to judge" the seriousness of Iraq's threat, or what kind of "unconventional" response was planned by Iraqi leader Saddam Hussein.
"As for an unconventional attack it may be one of two things.
"An attack with chemical or biological weapons - that would have very serious consequences for the regime in that it would be met with a proportional response and those responsible would be held to account.
"Secondly, he could use a human tide and we had signs last night that there were loudspeakers in south-west Baghdad signalling people should rise up and
march on the airport.
"That was pretty much in character to use civilians in that way as human shields in a way that might put them in danger."
He said Saddam Hussein's regime could "lash out" with chemical weapons at the last, but that depended on whether junior officers obeyed orders.
"On the one hand you could say when Saddam and his regime feel the game is up they may lash out in revenge.
"On the other hand there has to be a command and control system to use such
weapons, and it may be some of those in it will be disinclined to carry out their
orders because they know they will be held to account."
Air Marshal Burridge said US-led troops would approach Baghdad in the same "deliberate" way UK troops had approached the southern city of Basra.
"A difference is that this is the home of the regime, and when the regime
crumbles that's going to have an effect on the population of Baghdad generally,
and the Baathist militias and paramilitaries and all the other thugs and death
"We will make sure we know what's going on, where the clusters of really bad
people are, and will deal with them bit by bit, very deliberately.
"I'm talking about people who have lived above the law for 25 years.
"They have no ideology and they just know their own necks are on the line."